1. Field of the Disclosure
The disclosure generally relates to a method and apparatus for capturing and analyzing thermo-graphic images of moving objects. More particularly, the disclosure relates to a method and apparatus for correcting the distortion in thermo-graphic images caused when capturing an image of a moving object.
2. Brief Description of Related Technology
Infrared imaging cameras are well suited and have previously been used for monitoring thermal profiles of stationary targets. For example, portable imagers are commonly used in maintenance applications to detect hot spots in machinery. Similarly, portable images may be used to detect whether a boiler or molten metal container is in an acceptable temperature range. On-line cameras are available for process control applications, such as measuring the temperature of molded parts being ejected from a molding machinery. These types of imagers and cameras are limited in their usage, however, due to response time limitations. For example, the imagers and cameras may be limited to use with stationary or slow moving processes.
In a typical on-line application, a thermal snapshot is first taken of the object to be inspected. The resulting image is then analyzed using one or more techniques found in common vision systems. For example, the image may be analyzed by comparing it to a reference image and/or by looking for missing segments. Such thermal image may be used for checking upper and/or lower limits of acceptable temperatures.
The slow response time of current cameras and imagers, however, causes blurring in the image when the part is moving too quickly. For example, a large majority of process control applications are best suited for cameras operating in the 8-12 micron waveband, which utilizes a microbolometer detector with a typical response time of 100 milliseconds. Even with the faster 16 millisecond response time in an amorphous silicon detector there is still substantial blurring for most moving target applications.
As a result, the faster the part moves, the greater the blurring of the image. A blurred image does not yield sufficiently good results which are needed for many of the analyzing functions. In addition, a blurred image does not yield accurate temperature readings.